Abstract : Specifications, design considerations, and construction of an advanced spectrophotometer are discussed. This spectrophotometer represents a significant improvement over existing light measuring instruments. It is designed to measure light intensities in the visible spectrum (0.4 - 1.1 microns) with a relative accuracy of 1%. Transmitted or scattered light can be measured as a function of wavelength and direction. The wavelength resolution is adjustable down to 100 A. A small remote pickup unit, consisting of a photodiode and a lens system, is connected to the instrument by optical fibers and allows measurements up to six feet from the instrumentation. Although the spectrophotometer can be used in any work where extreme wavelength resolution is not needed, it was primarily designed for experiments with ice and snow. (Author)